Italy is currently going through a recession and electricity demand is declining around 3% annually, but traditional power generation is declining at over 14% annually while wind is growing at a rapid rate.On May 25, 2012, a sunny Saturday, Germany's solar power installations provided 22GW per hour of electricity - 50% of Germany's midday electricity demand. It was the first time Germany's solar facilities had generated over 20 GW of electricity. From Reuters - http://www.reuters.com/article/2012/05/26/us-climate-germany-solar-idUSBRE84P0FI20120526

In 2013 Spain became the first country where wind was the dominant supplier of electricity. It provided 20.9% of Spain's electricity demand, followed by nuclear at 20.8%. Nuclear generated more electricity but the nuclear power plants themselves used enough that the net electricity delivered to consumers was less than that of wind. Source: European Wind Energy Association at:

Italy's, and Germany's breakthrough days were exceptional but that they happened at all is indicative of what is possible and the direction many countries are taking. Italy is number 10 in the world in renewable electricity production, Germany is number 7.

All countries around the world are adding renewable energy sufficiently fast that by the time any data is published it is immediately out of date. Renewables in many instances have reached parity with fossil fuels in terms of installation cost.

The dominant renewable energy is still hydro-electric with a world wide generation of 3500 Tera Watt-Hrs in 2011. This represents only 2.4% annual growth over 12 years. There is no growth in developed countries. All the growth is coming from developing countries of which China accounts for about half the total worldwide growth. Once every river and creek is dammed, we will not see growth from hydro-electric world-wide. (The next few charts are from information available from the US Energy Information Agency at:

Wind energy (450 TW-Hrs in 2011) has recently become cheaper and is growing phenomenally fast - 25% compound annual growth rate over the 12 years from 2000-2011. If wind generation is able to keep up that pace it will overtake hydroelectric around 2024.

In the US, Wind Power installation pretty much depends on a set of tax credits which have to be renewed every few years. The result is that wind power installation virtually halts once the tax credit disappears. The tax credit is renewed periodically since the economics of wind power cuts across party lines with Republicans from Texas and the Midwest joining with Democrats from California and the North-East because of an installed base of wind generators in those states. This tax credit may soon no longer be necessary. One world-wide renewable energy supplier claims that Wind is now competitive in Europe and the US without subsidies, assuming only 25% wind capacity factor.

According to the American Wind Energy Association (obviously a biased source) wind power if maximally installed, could meet more than 40 percent of California's current electricity needs. The water consumption savings from wind projects in California total more than 2.8 billion gallons of water per year compared to the cooling needs of thermo-electric plants like coal, nuclear, and gas. Wind power generation currently installed in California will avoid over 7,840,000 metric tons of carbon dioxide emissions annually, the equivalent of taking nearly 1,400,000 cars off the road. C.f.:

This is a lot of energy, but no one wants to live near a wind farm (too noisy) so a more realistic estimate should be much less. The "Wind Vision" of the DoE (draft report) is that wind power will grow from 4% of US needs now to 10% in 2020, 30% in 2030, and 35% in 2050 at which time it will be the single largest electricity generator in the US. The DoE expects further cost reductions in wind energy production.http://www.awea.org/MediaCenter/pressrelease.aspx?ItemNumber=6445

Peak wind generation has met as much as 60% of demand in some regions of the US recently. The sun only shines half the time, but the wind blows day and night somewhere in the US and if there are enough wind generators spread around it can all balance out to a relatively constant flow of electricity.